Generally, an organic light emitting phenomenon refers to a phenomenon in which electric energy is converted into light energy by an organic material. An organic electronic element utilizing the organic light emitting phenomenon is usually configured to have a structure including an anode, a cathode, and an organic layer interposed therebetween. As such, in order to increase the efficiency and stability of an organic electronic element, the organic layer may be mostly provided in the form of a multilayer structure including layers made of different materials, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.
Materials useful for the organic layer in an organic electronic element may be classified into, depending on the function thereof, light emitting materials and charge transport materials, for example, a hole injection material, a hole transport material, an electron transport material, an electron injection material, etc. Further, the light emitting materials may be classified into high-molecular-weight materials and low-molecular-weight materials depending on the molecular weight thereof, and may also be classified into, depending on the emission mechanism thereof, fluorescent materials derived from the singlet excited state of electrons and phosphorescent materials derived from the triplet excited state of electrons. Furthermore, the light emitting materials may be classified into, depending on the emission color thereof, blue, green, and red light emitting materials, and yellow and orange light emitting materials necessary for better natural color reproduction.
In particular, thorough research is ongoing into organic materials which are inserted into a hole transport layer or a buffer layer to achieve excellent lifetime characteristics of an organic electronic element. To this end, a hole injection layer material is required, which has high hole mobility to an organic layer from an anode and exhibits high uniformity and low crystallinity upon forming a thin film after deposition.
Moreover, there is required to develop a hole injection layer material that retards penetration and diffusion of metal oxide into an organic layer from an anode (indium tin oxide (ITO)), which may be regarded as a reason for reduction in the lifetime of an organic electronic element, and also that has stability against Joule heat generated during the operation of an organic electronic element, namely, a high glass transition temperature. Also, it is reported that the low glass transition temperature of a hole transport layer material has a significant influence on the lifetime of an organic electronic element because the uniformity of the surface of a thin film is broken during the operation of the element. Furthermore, a deposition process is mainly applied to form an organic light emitting diode (OLED), and thus there is a need for a material that may endure such a deposition process, namely, a highly heat-resistant material.
Meanwhile, when only a single material is used as a light emitting material, there occur problems of shift of a maximum emission wavelength to a longer wavelength due to intermolecular interactions and lowering of the efficiency of the element due to deterioration in color purity or reduction in luminous efficiency. Hence, a host/dopant system may be adopted as the light emitting material in order to enhance the color purity and to increase the luminous efficiency through energy transfer. This is based on the principle that if a small amount of dopant having a smaller energy band gap than a host for a light emitting layer is mixed in the light emitting layer, then excitons generated from the light emitting layer are transported to the dopant, thus emitting light with high efficiency. With regard to this, as the wavelength of the host is shifted to the wavelength band of the dopant, light having a desired wavelength may be obtained depending on the type of dopant.
In order to allow an organic electronic element to sufficiently exhibit superior properties as above, it is prerequisite to support a material constituting an organic layer in the element, for example, a hole injection material, a hole transport material, a light emitting material, an electron transport material, an electron injection material, or the like, with a stable and efficient material. However, such stable and efficient organic layer materials for an organic electronic element have not yet been fully developed. Accordingly, there is a continuous need to develop new organic layer materials.
Recently, enhancements in the characteristics of elements by changing performance of individual materials are under study, and also improvements in color purity and efficiency due to the optimal optical thickness between an anode and a cathode in a top element having a resonant structure are regarded as important in terms of enhancing the performance of the element. Compared to a bottom element having a non-resonant structure, the top element is configured such that the produced light is reflected from the anode as a reflective film and is emitted from the cathode, remarkably increasing optical energy loss due to SPPs (Surface Plasmon Polaritons).
Thus, with the goal of improving the shape and efficiency of EL spectrum, formation of a capping layer on the top cathode is employed. Typically, as for SPP, electron emission is mainly carried out using four metals Al, Pt, Ag and Au, and surface plasmon is generated from the surface of the metal electrode. For example, when Ag is used for the cathode, emitted light is quenched by SPP due to the cathode Ag (light energy loss due to Ag), undesirably decreasing light efficiency.
Whereas, when the capping layer is used, SPPs are generated at the boundary between the MgAg electrode and the high-refractive-index organic material, of which TE (Transverse Electric) polarized light disappears on the CPL plane in a vertical direction by an evanescent wave, and TM (Transverse Magnetic) polarized light, which travels along the cathode and the capping layer, causes amplification of the wavelength by surface plasma resonance, thereby increasing the intensity of the peak, consequently making it possible to increase light efficiency and to effectively adjust the color purity.
Accordingly, an aspect of the present invention is intended to provide an organic electronic element including a light efficiency improving layer, which may exhibit high luminous efficiency, low driving voltage, improved color purity and long lifetime of the element, an electronic device including the same, and a compound for the same.
Specifically, in order to solve the problems encountered in the prior art and to accomplish the above aspect for high luminous efficiency, low driving voltage, improved color purity, high stability and long lifetime of the element, an aspect of the present invention is to provide an organic electronic element including a light efficiency improving layer using a compound represented by Chemical Formula 1 below:

wherein (1) R1, R2 and R3 are each independently selected from the group consisting of a C6 to C60 aryl group unsubstituted or substituted with one or more substituents selected from the group consisting of hydrogen, deuterium, halogen, a C1 to C20 alkyl group, a C1 to C20 alkoxy group, a C1 to C20 alkylamine group, a C1 to C20 alkylthiophene group, a C6 to C20 arylthiophene group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C3 to C20 cycloalkyl group, a C6 to C60 aryl group, a deuterium-substituted C6 to C20 aryl group, a C8 to C20 arylalkenyl group, a silane group, a boron group, a germanium group, and a C2 to C20 heterocyclic group;
a C2 to C60 heterocyclic group unsubstituted or substituted with one or more substituents selected from the group consisting of hydrogen, deuterium, halogen, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C1 to C20 alkoxy group, a C6 to C20 arylamine group, a C6 to C60 aryl group, a deuterium-substituted C6 to C20 aryl group, a C7 to C20 arylalkyl group, a C8 to C20 arylalkenyl group, a C2 to C20 heterocyclic group, a nitrile group and an acetylene group, and containing at least one of O, N, S, Si and P as a hetero atom; and
a C1 to C50 alkyl group unsubstituted or substituted with a substituent selected from the group consisting of a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C1 to C20 alkoxy group, a C6 to C60 aryl group, a C7 to C20 arylalkyl group, a C8 to C20 arylalkenyl group, a C2 to C20 heterocyclic group, a nitrile group and an acetylene group, and
(2) L1 and L2 are independently selected from the group consisting of a direct bond; a C6 to C60 arylene group unsubstituted or substituted with one or more substituents selected from the group consisting of nitro, nitrile, halogen, a C1 to C20 alkyl group, a C1 to C20 alkoxy group and an amino group; and a C2 to C60 heterocyclic group unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium, halogen, a silane group, a cyano group, a nitro group, a C1 to C20 alkoxy group, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C6 to C20 aryl group, a deuterium-substituted a C6 to C20 aryl group, a C3 to C20 cycloalkyl group, a C7 to C20 arylalkyl group and a C8 to C20 arylalkenyl group, and containing at least one of O, N, S, Si and P as a hetero atom.
More specifically, the compound represented by Chemical Formula 1 may be any one selected from the group consisting of Chemical Formulas 2 to 4 below.

In addition, aspects of the present invention are to provide an electronic device including the organic electronic element using the compound as above, and a compound for the organic electronic element, which is represented by the above chemical formula and plays a role in improving light efficiency.
Illustratively, the organic electronic element according to an embodiment of the present invention includes a first electrode; a second electrode; one or more organic layers formed between the first electrode and the second electrode; and a light efficiency improving layer formed on at least one of an upper side and a lower side of the first electrode and the second electrode, opposite to the side on which the organic layers are formed, wherein the light efficiency improving layer includes the compound represented by Chemical Formula 1. Further, the compound of Chemical Formula 1 may be used for an organic layer. As such, the organic layer may be at least one of a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer.
The light efficiency improving layer may be formed on at least one of the lower side of the first electrode and the upper side of the second electrode. Illustratively, the first electrode may be an anode formed of ITO including Ag, the second electrode may be a cathode including Mg—Ag, and the light efficiency improving layer may be formed on the upper side of the second electrode. Also, the second electrode may be a light transmissive cathode, and the light efficiency improving layer may be formed on the upper side of the second electrode.
Illustratively, the first electrode may be a light transmissive anode, and the light efficiency improving layer may be formed on the lower side of the first electrode.
Illustratively, when the organic layers are patterned for R, G and B pixels, the light efficiency improving layer may be formed in common to the R, G and B pixels. Further, the light efficiency improving layer may include at least one of a light efficiency improving layer-R formed on a region corresponding to the R pixel, a light efficiency improving layer-G formed on a region corresponding to the G pixel, and a light efficiency improving layer-B formed on a region corresponding to the B pixel, for R, G and B pixels of the organic layers.
Another embodiment of the present invention provides an electronic device including a display device, which includes the above described organic electronic element having the compound of Chemical Formula 1, and a control unit for controlling the display device. The organic electronic element according to an embodiment of the present invention may be any one selected from the group consisting of an OLED, an organic solar cell, an organic photoconductor (OPC), and an organic transistor (organic TFT).
As a light efficiency improving layer including a compound according to an embodiment of the present invention is provided, light efficiency of an organic electronic element according to an embodiment of the present invention can be remarkably improved, thus exhibiting high luminous efficiency, low driving voltage and greatly improved color purity and lifetime of the element.